Safety-valve



(No Model.)

J. 0. OHEEVER.

I SAFETY VALVE. No. 293,948.

X m p w T M w m N m H m m% 1 2 j NYMI wf caping steam I get the effect of a UNITED I STATES Pn'rnn'r JOHN O. OHEETER, OF BOSTOX, MASSACHUSETTS.

SAFETY-VALVE.

SPECIFICATION forming part of Letters Patent No. 298,948, dated February 19, 1884.

* Application filed July 9, 1883. (No model.)

To all whom it may concern.-

Be it known that I, JOHN O. Oi-rnnvnn, of Boston, in the county of Suffolk, in the State of Massachusetts, have invented certain new and useful Improvements in Safety-Valves, of which the following is a specification.

My invention relates to that class of valves in which the pressure exerted upon the valve bysteam is resisted by a spring, the construction being illustrated in the drawings. This object I attain by the mechanism illustrated in the accompanying drawings, in which Figure l is a vertical section, showing my invention as applied to a safety-valve. Fig. 2 is a horizontal section taken on line 00 .c of Fig. 1.

In the drawings, let 0 represent a valveseat, and D a valve. These and their immediately-connecting parts may be made in any of the well-known styles.

L L represent the valve-stem, having rigidly attached to it acircular disk, M, upon which the foot of the spring S rests.

N is a circular disk resting upon the top of the spring S, and loosely fitting the valve-stem L L. The disk M is held adj ustably in place by the screw-threaded tube K. As the screw K is in working connection with the fixed cap H, it is evident that by turning the said screw downward the pressure will be brought to bear upon the disk M, and through it upon the spring S, which pressure upon the spring is communicated by the disk M and valvestem L L to the safety-valve D.

A, Figs. 1 and 2, represents an outer casing immediately over the valve D, and serves to receive the escaping steam, which may be conducted away by the side pipe, B, or through openings B in the top, as shown. The side pipe, B, is used where it is desired to conduct the steam awayas, for instance, when the boiler is under cover; but I prefer the top opening, B, when the valve is applied to locomotives, for by dividing the column of esmuffler, which is a very important feature in a safetyvalve. l

IVithin the. casing A a casing, E E, is made, which completely surrounds and incloses the spring S, the disk M N, and a part of the valve-stem L L, as shown in Fig. 1. The inner and outer casing maybe cast in one piece, or the inner one maybe separate and inserted in the top of the outer casing. The inner casing, as heretofore described, at its lower end, is entirely closed, with the exception of an opening large enough for the passage of the valve-stem. This inncrcasing is a decided impror'ement over those in which the open bottoms are closed by a piston, and thereby presenting a surface that will cause too much friction by corrosion or otherwise, so as to prevent the free operation of the valves. By so constructing and arranging the two chambers relatively to each other, I protect the spring from extreme high and low temperature, and also more readily remove or adjust the tension of the spring without disturbing the casing. By this arrangement of the easing A and easing E, I completely protect the spring S from the action of escaping steam and its contained matter.

Between the walls of the casing A and the casing E E is a space, I? I, in which the escaping steam has a free circulation, which circulation of steam maintains the parts inolosed by the casing E at a high temperature, which insures them against being injured by frost.

I am aware of a safety-valve in which the inner casing is inserted in the outer casing before the device is made fast to the valve seat. This I do not claim, broadly.

Having thus described my invention, what I desire to secure by Letters Patent is- 1. In a safety-valve, the combination, with an outer casing, an inner casing suspended therefrom, and having an opening in the top for inserting the spring, of a spring, substantially as shown and described.

'2. In a safety-vali 'e, the combination, with an outer casing, an inner casing suspended therefrom, having a closely-fitting orifice for the valve-stem in its lower end, and opened at its upper end for the insertion of a spring, and means for adjusting the tension of the same, substantially as shown and described.

3. In a safety-valve, the combination of an outer casing having a steam-outlet, and adapted to fit the valve-scat, an inner casing suspended therefrom, and

having an opening at its top, a cap for the opening of the inner casthe sound of .the escaping steam is muffled, ing, with a spring and means for adjusting the substantially as shown. same, substantially as shown and described. T

4. 111 a safety-valve, the combination, with JOHL CHEEVER" 5 an outer casing, an inner casing suspended \Vitnesses:

therefrom, of openings at the top of the annu- "WILLIAM EnsoN, lar chamber formed by the casings, whereby HELEN M. FEEGAN. 

